Childhood sensorineural hearing loss: effects of combined exposure with aging or noise exposure later in life
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The aim of the study was to examine childhood high-frequency sensorineural hearing loss (HF-SNHL) and the effects of combined exposure with aging or noise exposure on HF hearing thresholds in adulthood. Population-based cohort study of 30,003 adults (mean age 40 years) underwent an audiometry and completed a hearing questionnaire. At age 7–13 years, the same people had participated in a longitudinal school hearing investigation, in which 283 participants were diagnosed with HF-SNHL [PTA 3–8 kHz ≥ 25 dB HL (mean 45 dB HL), worse hearing ear], and 29,720 participants had normal hearing thresholds. The effect of childhood HF-SNHL on adult hearing threshold was significantly moderated by age. Age stratified analyses showed that the difference in HF hearing thresholds between adults with and without childhood HF-SNHL was 33 dB (95 % CI 31–34) in young adults (n = 173, aged 20–39 years) and 37 dB (95 % CI 34–39) in middle-aged adults (n = 110, aged 40–56 years). The combined exposure of childhood HF-SNHL and noise exposure showed a simple additive effect. It appears to be a super-additive effect of childhood-onset HF-SNHL and aging on adult hearing thresholds. An explanation might be that already damaged hair cells are more susceptible to age-related degeneration. To exclude possible birth cohort effects, the finding should be confirmed by a study with several audiometries in adulthood.
KeywordsSensorineural hearing loss Aging Noise exposure Interaction
We are grateful to the late Dr. H. M. Fabritius and Namsos Hospital for making the SHINT data available to us. We are grateful to Howard Hoffman for the help with obtaining funding. The Nord-Trøndelag Health Study (The HUNT Study) is a collaboration between the HUNT Research Center, Faculty of Medicine, Norwegian University of Science and Technology (NTNU), Verdal, Norwegian Institute of Public Health, and Nord-Trøndelag (NT) County Council. The NT County Health Officer and the Community Health Officers in Levanger and other municipalities provided organizational and other practical support. We also thank the NTHLS team for their diligence. The NTHLS, which is a part of HUNT, was funded by the National Institute on Deafness and Other Communication Disorders (NIDCD), NIH, research contract No. N01-DC-6–2104. The present study was supported by a grant from The Extra Foundation: Health and Rehabilitation through the member organization, The National Association of Hard of Hearing.
Conflict of interest
The NTHLS, which is a part of HUNT, was funded by the National Institute on Deafness and Other Communication Disorders (NIDCD), NIH, research contract No. N01-DC-6–2104. The present study was supported by a grant from The Extra Foundation: Health and Rehabilitation through the member organization, The National Association of Hard of Hearing. The funding source had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication. All funding has followed the guidelines on good publication practice. There was independence between researchers and funders/sponsors. All authors declare that they have no conflicts of interest. The submission complies with the ICMJE authorship definition.
The manuscript has not been submitted to more than one journal for simultaneous consideration. The manuscript has not been published previously (partly or in full). A single study is not split up into several parts to increase the quantity of submissions and submitted to various journals or to one journal over time. No data have been fabricated or manipulated (including images) to support your conclusions. No data, text, or theories by others are presented as if they were our own (“plagiarism”). Consent to submit has been received explicitly from all co-authors, as well as from the responsible authorities—tacitly or explicitly—at the institute/organization where the work has been carried out. Authors whose names appear on the submission have contributed sufficiently to the scientific work and therefore share collective responsibility and accountability for the results.
Research involving human participants
The research is in compliance with the Norwegian Data Inspectorate and the Norwegian Regional Committee for Medical Research Ethics. We do not possess any person identifiable data. For all individual participants included in the study, informed consent was obtained. For this type of study, no formal consent is required.
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